Sheet processing apparatus

Abstract

In a sheet processing apparatus that, for example, sorts or staples sheets after image formation, when preceding finishing is not completed on a processing tray, a third sheet fed anew into awaiting tray of a sheet placing member configuring a sheet waiting unit, which temporarily puts a sheet conveyed thereto on standby, is stacked to be shifted such that leading ends of second and third sheets are located further on a conveying direction upstream side than a leading end of a first sheet. Consequently, longitudinal alignment in the processing tray after that is surely performed.

1. A sheet processing device, comprising:
 a conveying member configured to convey a first, second, and third sheets; 
 a stacking member configured to stack the first, second and third sheets; 
 a controller configured to stack the first, second and third sheets on the stacking member in a state where rear ends of the second and third sheets are shifted nearer to a conveying direction upstream side than a rear end of the first sheet by the stacking member; 
 a first aligning member configured to arranged at the back end side of the stacked first, second, and third sheets on the stacking member; and 
 a second aligning member configured to slide the first, second, third sheets stacked in the state toward the first aligning member, the second aligning member configured to align the first, second, third sheets by striking the rear ends of the second and third sheets against the first aligning member before striking the rear end of the first sheet. 
 
     
     
       2. The sheet processing device according to  claim 1 , wherein the second aligning member has:
 a first member in contact with a bottom surface of the first sheet; 
 a second member in contact with atop surface of the third sheet; wherein 
 the controller slides the second sheet between the first and third sheets to the rear end side by using the first member to slide the first sheet, and by using the second member to slide the third sheet. 
 
     
     
       3. The sheet processing device according to  claim 2 , wherein the stacking member having a first tray and a second tray, the first tray holding conveyed the first, second, and third sheets by the conveying member in the state, the second tray being located under the first tray;
 the controller is configured to make the first tray drop the first, second, and third sheets to the second tray, and 
 the second aligning member is configured to strike the first, second, and third sheets on the second tray to the first aligning member arranged at the rear end of sheet of the second tray. 
 
     
     
       4. The sheet processing device according to  claim 3 , further comprising a claiming member configured to clamp the rear end of the sheet on the first tray; the first tray is inclined in a manner that a rear end side is lower than a front end side. 
     
     
       5. The sheet processing device according to  claim 3 , wherein the controller is configured to convey subsequent sheets onto the second tray one sheet at a time through the first, second, and third sheets are dropped onto the second tray. 
     
     
       6. The sheet processing device according to  claim 3 , wherein the third sheet is placed in a manner aligned with the second sheet. 
     
     
       7. The sheet processing device according to  claim 3 , further comprising:
 a rotating member that is provided above in a conveying direction downstream side of the sheet and supported to be capable of rising and falling, and 
 a switching member that switches the rotating member to a lifted position and a lowered position; 
 wherein the controller drives the switching member and controls conveying a front end of the second sheet to the vicinity of the rotating member; 
 lifting the rotating member that sandwiches the first sheet to a lifting position; and 
 chucking the second sheet. 
 
     
     
       8. The sheet processing device according to  claim 7 , wherein the controller drives the switching member and controls conveying a front end of the third sheet to the vicinity of the rotating member;
 lifting the rotating member that presses the first sheet and the second sheet to a lifting position; 
 rotating the rotating member in a conveying direction at the lifting position; 
 lowering the rotating member at the lifting position by keeping the rotating member rotating in the conveying direction; 
 stopping rotation of the rotating member; and 
 placing the third sheet by aligning a front end position of the third sheet with a front end position of the second sheet without changing a shifted positional relationship between the first sheet and the second sheet. 
 
     
     
       9. The sheet processing device according to  claim 8 , further comprising:
 a timer that counts a sheet interval time of sheets supplied for processing; wherein 
 the controller controls a number of sheets to be buffered according to the sheet interval time. 
 
     
     
       10. A sheet processing device, comprising:
 a conveying means for conveying a first, second, and third sheets; 
 a stacking means for stacking the first, second, and third sheets; 
 a control means for stacking the first, second, and third sheets on the stacking means in a state where rear ends of the second and third sheets are shifted nearer to a conveying direction upstream side than a rear end of the first sheet by the stacking means; 
 a first aligning means for arranged at the back end side of stacked first, second, and third sheets on the stacking means; and 
 a second aligning means for sliding the first, second, third sheets are stacked in the state toward the first aligning means, the second aligning means configured to align the first, second, third sheets by striking the rear ends of the second and third sheets against the first aligning means before striking the rear end of the first sheet. 
 
     
     
       11. The sheet processing device according to  claim 10 , wherein the second aligning means has:
 a first means for contacting with a bottom surface of the first sheet; 
 a second means for contacting with a top surface of the third sheet; wherein 
 the control means slides the second sheet between the first and third sheets to the rear end side by using the first means to slide the first sheet, and by using the second means to slide the third sheet. 
 
     
     
       12. The sheet processing device according to  claim 11 , wherein the stacking means having a first tray means and a second tray means, the first tray means holding conveyed the first, second, and third sheets by the conveying means in the state, the second try means being located under the first tray means;
 the control, means for making the first tray means drop the first, second, and third sheets to the second tray means; and 
 the second aligning means is configured to strike the first, second, and third sheets on the second tray means to the first aligning means arranged at the rear end of sheet of the second tray means. 
 
     
     
       13. The sheet processing device according to  claim 12 , further comprising a claiming means for claiming the rear end of sheet on the first tray means; the first tray means is inclined in a manner that a rear end side is lower than a front end side. 
     
     
       14. The sheet processing device according to  claim 12 , wherein the control means is configured to convey subsequent sheets on the second tray means one sheet at a time through the first tray means after the first, second, and third sheets are dropped onto the second tray means. 
     
     
       15. The sheet processing device according to  claim 12 , wherein the third sheet is placed in a manner aligned with the second sheet. 
     
     
       16. The sheet processing device according to  claim 12 , further comprising:
 a rotating means for providing above in a conveying direction downstream side of the sheet and supported to be capable of rising and falling, and 
 a switching means for switching the rotating means to a lifted position and a lowered position; 
 wherein the control means drives the switching means and controls conveying a front end of the second sheet to the vicinity of the rotating means; 
 lifting the rotating means that sandwiches the first sheet to a lifting position; and 
 chucking the second sheet. 
 
     
     
       17. The sheet processing device according to  claim 16 , wherein the control means drives the switching means and controls conveying a front end of the third sheet to the vicinity of the rotating means;
 lifting the rotating means that presses the first sheet and the second sheet to a lifting position; 
 rotating the rotating means in a conveying direction at the lifting position; 
 lowering the rotating means at the lifting position by keeping the rotating means rotating in the conveying direction; 
 stopping rotation of the rotating means; and 
 placing the third sheet by aligning a front end position of the third sheet with a front end position of the second sheet without changing a shifted positional relationship between the first sheet and the second sheet. 
 
     
     
       18. The sheet processing device according to  claim 17 , further comprising:
 a timer means for counting a sheet interval time of sheets supplied for processing; wherein 
 the control means controls a number of sheets to be buffered according to the sheet interval time.